1. Field of the Invention
The present disclosure relates to a holographic characterization and playback apparatus, and more particularly, to a holographic characterization and playback apparatus in which a scattering lens is disposed on an optical path of a probe light.
2. Description of the Related Art
In holographic data storage, recording involves storing information in the form of interference fringes into a material such as a photopolymer that responds to the intensity of light. The interference fringes are formed by using two laser beams. That is, the interference fringe formed by interference between the reference light and the signal light is recorded by causing a chemical or physical change in the photosensitive storage medium. In order to play back the information from the interference fringes recorded in the above manner, reference light similar to the light used for recording is irradiated onto the interference fringes recorded on the storage medium. The irradiated reference light is diffracted by the interference fringe, whereby the signal light is restored and the information is played back.
The recording method using such hologram technologies includes a volume holography method for recording/playing back information on a page basis, and a microholography method for recording/playing back information with a single bit. Although the volume holography method has the advantage of processing a large amount of information simultaneously, it is difficult to commercialize it as an information storage device for use by the general consumers since it requires precision adjustment of an optical system.
On the other hand, the microholography method forms fine interference fringes by an interference of two focused light beams at a focal point, in which the interference fringes are recorded, while a position on a plane of the storage medium is moved thus forming layers and these layers are recorded and superposed in the depth direction of the storage medium so that the information is recorded three-dimensionally on the storage medium.
However, a general microholographic recording/reproducing device employs an optical system simply composed of a lens group such as a focusing lens and an objective lens, thus providing somewhat limited performance in 3D focusing and multi-focusing.